U.S. patent application number 15/487043 was filed with the patent office on 2018-10-18 for image scanning apparatus.
The applicant listed for this patent is Microtek International Inc.. Invention is credited to Chin-Lai WU.
Application Number | 20180302531 15/487043 |
Document ID | / |
Family ID | 63791057 |
Filed Date | 2018-10-18 |
United States Patent
Application |
20180302531 |
Kind Code |
A1 |
WU; Chin-Lai |
October 18, 2018 |
IMAGE SCANNING APPARATUS
Abstract
An image scanning apparatus captures multiple images of an
object corresponding to different heights at each scanning
position, analyzes the resolutions of the multiple images to choose
one best partial image, and combines the partial images at
different scanning positions to produce a scanned image of the
object, so as to improve the resolution of the scanned image.
Inventors: |
WU; Chin-Lai; (Hsinchu,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Microtek International Inc. |
Hsinchu |
|
TW |
|
|
Family ID: |
63791057 |
Appl. No.: |
15/487043 |
Filed: |
April 13, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04N 1/00018 20130101;
H04N 1/3876 20130101; H04N 1/193 20130101; H04N 1/40056
20130101 |
International
Class: |
H04N 1/40 20060101
H04N001/40; H04N 1/00 20060101 H04N001/00; H04N 1/193 20060101
H04N001/193 |
Claims
1. An image scanning apparatus comprising: a scanning light source
to provide a light to irradiate an object; an image capturing unit
disposed opposite to the object; a first driving unit to drive the
image capturing unit and the object to move with respect to each
other among multiple scanning positions, so as to scan the object;
a second driving unit connected to the image capturing unit to
drive the image capturing unit to move along a height direction,
wherein the height direction is perpendicular to a surface of the
object; and an image processing unit electrically connected to the
image capturing unit, the first driving unit and the second driving
unit, wherein the image capturing unit captures multiple images of
the object corresponding to different heights when moving along the
height direction at each the scanning position and delivers the
multiple images to the image processing unit, and the image
processing unit outputs one of the multiple images as one partial
image at the scanning position and combines the partial image at
each different scanning position to produce a scanned image of the
object.
2. The image scanning apparatus according to claim 1, wherein the
image processing unit further comprises a comparing unit to
calculate multiple Modulation transfer function values of the
multiple images and output the partial image, wherein the
Modulation transfer function value of the partial image is the
maximum Modulation transfer function value.
3. The image scanning apparatus according to claim 1, wherein the
image processing unit further comprises a control unit to produce a
control signal to the first driving unit according to the partial
image, and the first driving unit drives the image capturing unit
and the object to move with respect to each other to adjacent the
scanning position according to the control signal.
4. The image scanning apparatus according to claim 1, wherein the
image processing unit further comprises a memory unit to store the
partial image.
5. The image scanning apparatus according to claim 1, wherein the
second driving unit comprises a stepper motor.
6. The image scanning apparatus according to claim 1, wherein an
image capturing number of the image capturing unit for capturing
multiple images at the same one scanning position is more than or
equal to a quotient of a maximum height value of the object divided
by a value of the depth of field of the image capturing unit.
7. The image scanning apparatus according to claim 1, wherein the
first driving unit comprises a stepper motor connected to the image
capturing unit.
8. The image scanning apparatus according to claim 1, wherein the
image capturing unit comprises a charge coupled device or a contact
image sensor.
9. The image scanning apparatus according to claim 1, wherein the
image capturing unit comprises a Line-Scan light-sensing
device.
10. The image scanning apparatus according to claim 1, wherein the
scanning light source and the image capturing unit are disposed a t
opposite sides of the object.
11. The image scanning apparatus according to claim 1, wherein the
scanning light source and the image capturing unit are disposed a t
the same side of the object.
12. The image scanning apparatus according to claim 1, further
comprising a platform having a transparent material.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to an image scanning
apparatus, and more particularly to an image scanning apparatus
that can improve the resolution of the scanned image.
2. Description of the Prior Art
[0002] In order to improve the scanning resolution, a traditional
image scanning apparatus usually adopts two more scanning
processes. First, a first scan is conducted with a lower resolution
to obtain a focus map of the overall image. Then, a second scan is
conducted with the resolution adjusted to the actually needed
resolution and with the focal length in the height direction
adjusted according to the foregoing focus map. Therefore, the
traditional image scanning apparatus needs to conduct two focusing
and scanning processes to obtain a scanned image of high
resolution, which leads to the complex operation and the long
scanning time.
[0003] Thus, the most important goal for now is to provide an image
scanning apparatus that can improve the resolution of the scanned
image.
SUMMARY OF THE INVENTION
[0004] The present invention is directed to provide an image
scanning apparatus, which uses an image processing unit and an
image capturing unit to capture multiple images of an object
corresponding to different heights at each scanning position,
analyze the resolutions of the multiple images to choose one best
partial image, and combine the partial images at different scanning
positions to produce a scanned image of the object, so as to
improve the resolution of the scanned image.
[0005] An image scanning apparatus of one embodiment of the present
invention includes a scanning light source, an image capturing
unit, a first driving unit, a second driving unit and an image
processing unit. The scanning light source provides a light to
irradiate an object. The first driving unit drives the image
capturing unit and the object to move with respect to each other
among multiple scanning positions, so as to scan the object. The
second driving unit is connected to the image capturing unit, and
the second driving unit drives the image capturing unit to move
along a height direction, wherein the height direction is
perpendicular to a surface of the object. The image processing unit
is electrically connected to the image capturing unit, the first
driving unit and the second driving unit, wherein the image
capturing unit captures multiple images of the object corresponding
to different heights at each scanning position and delivers the
multiple images to the image processing unit, and the image
processing unit outputs one of the multiple images as one partial
image at the scanning position and combines the partial image at
each different scanning position to produce a scanned image of the
object.
[0006] The objective, technologies, features and advantages of the
present invention will become apparent from the following
description in conjunction with the accompanying drawings wherein
certain embodiments of the present invention are set forth by way
of illustration and example.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic view, showing an image scanning
apparatus of one embodiment of the present invention.
[0008] FIG. 2 is a schematic view, showing an image processing unit
of one embodiment of the present invention.
[0009] FIG. 3 is a schematic view, showing an image scanning
apparatus of another embodiment of the present invention.
[0010] FIG. 4 is a schematic view, showing an image scanning
apparatus of yet another embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0011] Various embodiments of the present invention will be
described in detail below and illustrated in conjunction with the
accompanying drawings. In addition to these detailed descriptions,
the present invention can be widely implemented in other
embodiments, and apparent alternations, modifications and
equivalent changes of any mentioned embodiments are all included
within the scope of the present invention and based on the scope of
the Claims. In the descriptions of the specification, in order to
make readers have a more complete understanding about the present
invention, many specific details are provided; however, the present
invention may be implemented without parts of or all the specific
details. In addition, the well-known steps or elements are not
described in detail, in order to avoid unnecessary limitations to
the present invention. Same or similar elements in Figures will be
indicated by same or similar reference numbers. It is noted that
the Figures are schematic and may not represent the actual size or
number of the elements. For clearness of the Figures, some details
may not be fully depicted.
[0012] Referring to FIG. 1 together, an image scanning apparatus of
one embodiment of the present invention includes a scanning light
source 10, an image capturing unit 20, a first driving unit 30, a
second driving unit 40 and an image processing unit 50. The
scanning light source 10 provides a light L to irradiate an object
A. The first driving unit 30 drives the image capturing unit 20 and
the object A to move with respect to each other among multiple
scanning positions along a scanning direction X, so as to scan the
object A. In one embodiment, if the object A is a transparent
material and the scanning light source 10 and the image capturing
unit 20 are disposed at opposite sides of the object A
respectively, then the image capturing unit 20 receives the light L
transmitting through the object A, so as to realize a transmission
image scanning apparatus, which is not a limitation. In another
embodiment, the scanning light source (not shown) and the image
capturing unit 20 are disposed at the same side of the object A
respectively, and the image capturing unit 20 receives the light L
reflected by the object A, so as to realize a reflecting image
scanning apparatus. The second driving unit 40 is connected to the
image capturing unit 20, and the second driving unit 40 drives the
image capturing unit 20 to move along a height direction Z, wherein
the height direction Z is perpendicular to a surface of the object
A, i.e., perpendicular to the scanning direction X. In one
embodiment, the image capturing unit 20 includes a Line-Scan
light-sensing device. In one embodiment, the image capturing unit
20 includes a charge coupled device (CCD) that may be coordinated
with a single lens or a lens set, which may not be a limitation. In
another embodiment, the image capturing unit 20 includes a contact
image sensor (CIS), which only needs multiple small rod lens for
imaging and is closer to the object A, so that a light path of the
light L is shortened significantly and the contrast of the scanned
image is improved directly.
[0013] In one embodiment, the first driving unit 30 or the second
driving unit 40 includes a pulse driving unit. For example, the
first driving unit 30 or the second driving unit 40 is a stepper
motor. It may be understood that the pulse driving unit is a
driving device that rotates in a particular angle gradually through
the pulse control and usually adopts the open loop control mode for
processing. Therefore, the pulse driving unit may achieve the
accurate control of the position and speed without a feedback
device for the position detection and speed detection and have an
excellent stability. Therefore, the pulse driving unit may save the
vast and complex hardware assembly space to achieve the design
effect of lightweight, and reduce the production cost.
[0014] Continued with the foregoing descriptions, the image
processing unit 50 is electrically connected to the image capturing
unit 20, the first driving unit 30 and the second driving unit 40.
The image capturing unit 50 captures multiple images of the object
corresponding to different heights at each scanning position and
delivers the multiple images to the image processing unit 50.
[0015] In addition, the image processing unit 50 receives the
multiple images, outputs the clearest one of the multiple images as
one partial image at the scanning position and combines the partial
image at each different scanning position to produce a scanned
image of the object A.
[0016] Referring to FIG. 1 and FIG. 2 together, in one embodiment,
the image processing unit 50 further includes a memory unit 503
which stores the partial images of the object A, such as a partial
image of a strip area, so that the image processing unit 50 may
combine the different partial images at different scanning
positions. In another embodiment, the image processing unit 50
further includes a comparing unit 501 which calculates multiple
Modulation transfer function values corresponding to the multiple
images and outputs the partial image, wherein the Modulation
transfer function value of the partial image is the maximum
Modulation transfer function value, i.e., having the best
resolution. In one embodiment, the image processing unit 50 further
includes a control unit 502 which produces a first control signal
to the first driving unit 30 according to the partial image. The
first driving unit 30 drives the image capturing unit 20 and the
object A to move with respect to each other to an adjacent scanning
position according to the first control signal. For example, after
the image processing unit has obtained a partial image at a
scanning position, it means that the partial image that has the
best focusing quality at the scanning position has been obtained.
Therefore, the first driving unit may be commanded to drive the
image capturing unit to move to another scanning position to
capture multiple images of the object corresponding to different
heights, and the above-mentioned steps of the modulation transfer
function (MTF) analysis and the image selection may be repeated, so
as to obtain another partial image that has the best focusing
quality at the another scanning position.
[0017] In another embodiment, the image processing unit 50 may also
produce a second control signal to the second driving unit 40
through the control unit 502 to drive the image capturing unit 20
to move along a height direction Z at the same scanning position,
and at the same time, the image processing unit 50 controls the
image capturing unit 20 to capture multiple images of the object
corresponding to different heights.
[0018] It is needed to be explained that an image capturing number
for capturing multiple images at the same one scanning position is
mainly determined by a value of the depth of field D of the image
capturing unit 20 and a maximum height value H of the object. In
one embodiment, if the maximum height value of the surface of the
object A is H and the value of the depth of field of the image
capturing unit 20 is D, then the image capturing number of the
image capturing unit 20 for capturing multiple images at the same
one scanning position is more than or equal to a quotient of the
maximum height value H of the object A divided by the value of the
depth of field D of the image capturing unit 20. For example, as to
the object A that has an uneven surface, if the surface thereof has
a maximum height value of 5 mm and the value of the depth of field
of the image capturing unit 20 is 2 mm, then the image capturing
number of the image capturing unit 20 for capturing multiple images
at the same one scanning position is more than or equal to the
integer value of [5/2], i.e., 3 at least. In other words, the
second driving unit 40 needs to drive the image capturing unit 20
to move along the height direction Z at least 3 times, and the
image processing unit 50 controls the image capturing unit 20 to
capture image 3 times at different Z axis heights. In another
embodiment, the image processing unit 50 may preset an image
capturing number of 10, and obtain 10 images at different Z axis
heights to conduct subsequent image analysis, such as the
above-mentioned MTF analysis and the image selection. It may be
understood that the focusing quality of the scanned image may be
adjusted through the image capturing number in the Z axis height
direction. For example, capturing 20 images at the same one
scanning position, compared with capturing 10 images, should have a
better focusing quality and may obtain a better partial image.
Those skilled in the art may modify and change, and may not be
limited to this.
[0019] Referring to FIG. 3, in one embodiment, the image scanning
apparatus further includes a platform 60 having a transparent
material. The object A may be a transparent material as well, and
the scanning light source 10 and the image capturing unit 20 are
disposed at opposite sides of the platform 60 respectively, so as
to realize a transmission image scanning apparatus. Referring to
FIG. 4, in another embodiment, the scanning light source 10 and the
image capturing unit 20 are disposed at the same side of the
platform 60 respectively, so as to realize a reflecting image
scanning apparatus. In another embodiment, the first driving unit
30 is connected to the platform 60, and the first driving unit 30
drives the platform 50 to move along the scanning direction X, so
as to scan the object A. In another embodiment, the first driving
unit 30 is connected to the image capturing unit 20 to drive the
image capturing unit 20 to scan the object A. In yet another
embodiment, the scanning light source 10 that is connected to the
first driving unit 30 through a connecting rod component may scan
the object A synchronously with the image capturing unit 20. Those
skilled in the art may modify and change, and may not be limited to
this.
[0020] To sum up the foregoing descriptions, the image scanning
system of the present invention uses an image processing unit and
an image capturing unit to capture multiple images of an object
corresponding to different heights at each scanning position,
analyze the resolutions of the multiple images to choose one best
partial image, and combine the partial images at different scanning
positions to produce a scanned image of the object, so as to
improve the resolution of the scanned image. Thus, the image
scanning system of the present invention may obtain a scanned image
of high resolution through a one-time scanning process. In
addition, compared with the traditional image scanning apparatus,
the image scanning apparatus of the present invention may save the
vast and complex hardware assembly space to achieve the design
effect of lightweight, and reduce the production cost.
[0021] The above embodiments are only for describing the subject
matters and characteristics of the present invention, which purpose
is to make those skilled in the art understand the content of the
present invention and implement accordingly, and can not be used to
limit the scope of the present invention. Any equivalent change or
modification in accordance with the spirit disclosed in the present
invention should fall within the scope of the present
invention.
* * * * *